SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dc33eaa139cda0db3363848ec70f1876f0624e8c6e4a98153b30d1060608df6' 
  AND token = 'J2y9QnPqDOQ1SidtBmN1TvP5osW66ZdxT2iy2CIjQmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}